A Twitter-based voluntary organisation is poised to launch its global fundraising festival on Thursday.

Twestival in London, which is already a sell-out, has been organised solely by volunteers. All money raised will go directly to the charity.

The event is backing safe drinking water charity, 'charity: water', as it prepares to go live in 160 cities worldwide.

Scott Harrison, founder of 'charity: water' said, 'The need for, and right to clean water is universal, so I'm delighted we're a cause that the international Twitter community is embracing.'

Amanda Rose, global event organiser, said, 'We're already blown away by the global reception and how keen people are to invest their time and energy for free to the Twestival and get behind charity: water.'

The project, which started as the brainchild of PROs Tim Hoang (Porter Novelli), Tom Malcolm (Diffusion PR) and Ben Matthews (Hotwire PR), grew from a 300 person, London-based meet up.